Printing ink



- manently retaining t Patented Apr 8, 1924.

g ET STATES WILLIAM J. MCELROY, OF NEW YORK, AND JOHN CLARKE, 0FKANHASSET, NEW YORK, ASSIGNORS TO ALCHEIBUC GOLD COMPANY, INC., ACORPORATION OF NEW YORK.

PRINTING INK.

Ho Drawing.

To all whom it may concern:

Be it known that we, WILLIAM J. Mo- ELRoY, a citizen of the UnitedStates, and a resident of the borough of Manhattan, city, county, andState of New York, and J OHN CLARKE, a citizen of the United States, anda resident of the village of Manhasset, town of North Hempstead, countyof Nassau, and State of New York, have invented a new and usefulImprovement in Printing Inks, of which the following is a description,as well as of the manner and rocess of making, constructing,compounding, and using the same, in such full, clear, concise, and exactterms as to enable an erson skilled. in the art or science to whic itappertains or with which it is most nearly connected to make, construct,compound, and use the same.

Our invention relates generally to printing inks and particularly tothose having metallic powders as their pigments.

The objects of our invention are the production of improved printinginks adapted for general use and more especially for use in embossingand die-printing upon bookcloth, leather and other materials commonlyused for book-casings; particular objects are the production of inks ofthis class which shall be adapted for application by a heated die, plateor other impression member, reheated to embossing temperatures. and wich shall be characterized by the qualities of drying immediately underthe relatively high temperatures preferred in embossing metallicpowders; and having properties 0 strongly adhering to and coveringsmoothly, evenly and completely the surface upon which they are stamped;of bein rendered lustrous by the heat of the meta by which they areimpressed u on such object; of pereir original color and luster withouttarnishing or :tading; of high boiling point and of low volatility.

Further objects are the rovision of an ink with the foregoing qu itieswhich can be mixed ready for use by the manufacturer and which will notcorrode or otherwise deteriorate in the container, and which, when ackaed, and transported shall remain in its original state with itsqualities and both its ph sical and chemical conditions unimpaired evenatter long lapse of it Our present invention consists in the dis coverythat printing inks such as set forth in our Patent No. 1,450,692, mayattain the Application filed July 25, 1922. Serial No. 677,429.

desired attributes above recited, particularly as to covering and lusterqualities to a highly superior de ree by employing as the metallicpigment to mixed with the highly viscous vehicle described, a mixture ofbronze powders, such mixture being composed of bronze owder of thefineness customarily employed in making inks, namely, that exam led bythe grade known commercially as emmerdingers Special No.. 1, to whichhas been added a more comminuted powder exampled by the grade knowngenerally in the trade as lining. We have further discovered that withsuch com osite powder, the heavybodied pigment ve .icles referred to inour aforesaid patent, and whose composition is hereinafter exampled,combine to make an ink in which the powdered metallic pigment, by virtueof the amount thereof in a state of fine subdivision, and by virtue ofthe high viscosity of the vehicle, will tend to remain in suspension aslong as the ink is fluid.

The stamped or embossed or printed impression obtained with this inkaffords a moreintense igmentation, and. when dried, is more pliab 0 thanthat obtainable either with the coarser particles used alone or with thefiner articles used alone. This is apparently ause the former leavesmicroscopic interstices between the articles, while the latter roducestoo smootli or fiat a surface to re ect light in the manner the coarserindividual particles do when present, hence the desired glance orbrilliance of luster is lacking. vThe best results are attained by theuse of the two grades in substantially their: relative proportionshereinafter examp e As an example of the preferred proportions of-theingredients named, we take, by weight,

per cent terpineol and 5 per cent rosm oil, and stir ough y mixed.

With 84 per cent of this mixture we incorporate 16 per cent of powderedcumarone resin e. g., that known under the trade name of umar, and warmthis mixture upon a water-bath at centigrade, stirring meanwhile, untilthe Cumar is thoroughly dissolved, which will result in about 20 minuteswith vigorous stirring. The batch is then allowed to cool. From thisbatch we hire onethird and add thereto two'thirds of powder, both byweight This mir until thorture is then stirred until the bronze powderis thoroughly and evenly incorporated. The ink resulting is .of past-yand semi-fluid consistenc similar to that of printing inks genera 1y.

As the metallic pigment above intended, we prefer a mixture of bronzepowder of the grade known commercially as Hemmerdingers Special No. 1,with 80 per cent of which is mixed 2.0 per cent of the finer grade ofbronze powders known generally in the trade as lining, a more finelycomminuted species of such powders, such species being that produced inthe process of usual manufacture of bronze powders by air-floating fromthe mill those particles which have been reduced to the state ofsubdivision of fine, almost impalpable, dust.

The proportions above exampled may be varied somewhat withoutappreciable variation of the product. I

While thus specifying terpineol and rosin oil as the constituentspreferred of our binder solvent vehicle, we wish to be understood astypifying thereby a binder vehicle having the desired properties assuch, first, of an active solvent of the synthetic resins named; second,as of the desired bodyadapted to maintain the bronze powders insustained suspension; third, as of the requisite degree of volatility tobe driven off by the temperature used in embossing metallic pigments toimpart the desired luster thereto; fourth, affording that degree ofplasticity and elasticity to the impression which w ll prevent itscracking; fifth, the necessary neutrality which will preserve themetallic particles from corrosion on standing when mixed in ink form;sixth, which shall not cause the impressed characters to tarnish; andseventh, which shall be colorless or of such color as will not detractfrom the desired metallic luster. Within the limitations imposed bythese criteria, the binder vehicle may be any of the suitable solventsor combinations thereof. This printing composition is primarily intendedfor printing book covers which, when of cloth, are prepared as caseswith a strong coating of glue to hold the cloth to the backing. s theboiling point of the vehicle specified is approximately 428 Fahrenheit,the impression temperature must suffice to drive off the volatilesolvent, that the impression may be dry, but must not be so high as todraw the glue through the cloth and thereby cause blisters in theimpression or darken it. Preferably,

therefore, the described composition should be used as an ink at atemperature substantially that of the boiling point of the solventvehicle. As will be obvious, however, the ink set forth may be used atlower tempera tures, or cold, and the impression artificially driedthereafter,

By virtue of the comparatively high spe clfic gravity of the syntheticresins produced as condensation products of naphtha, and the heavy bodyof the solvent therefor herein named, the solution obtained affords anespecially valuable vehicle for the metallic pigments in that thetendency of the bronze powder to settle is checked and a persistentsuspension thereof is attained.

Having thus described the preferred embodiment of cum invention and thebest method now known to us of producing and usefully applying same, weclaim:

1. A printing composition comprising a finely divided metallic igmentconsisting of a mixture of the less ne grade of bronze powders with asubstantial quantity of the finer grade of bronze powders resultant fromre-grinding the former grade added thereto, a neutral binder, a viscoussolvent for said binder of low volatility, the dissolved binderconstitutin a vehicle for the pigment of such viscosity that the pigmenttends to remain in suspension therein.

2. A printing composition comprising a binder, a highly viscous solventtherefor of low volatilit and a powdered metallic pigment consisting ofa mixture of bronze powders of two grades of fineness, the quantityratio between the grades being substantially four of one grade to one ofthefiner grade by weight, the latter grade being of the fineness oflinings.

3. A printing ink containin pigment consisting in part of ders of thegrade known as linings, such part substantially exceeding the percentageof this grade normally present in bronze owders which have not beensubject to air oating.

4. A 1pr a metal ic a metallic ronze powinting ink compositioncontaining pigment comprising a mixture of bronze powders of two gradesof fineness, as

follows: 80 per cent of a grade coarser than that identified as liningand per cent of lining, Cumar, and a solvent for said Cumar adapted tomaintain the metallic pigment in suspension.

WILLIAM J. MoELROY. JOHN CLARKE.

